Rotating electric sign device



Oct. 12, 1965 C, Q GLASGOW 3,210,872

ROTATING ELECTRIC SIGN DEVICE Tlc-: 1

Oct. 12, 1965 C 0- GLASGOW 3,210,872

ROTATING ELECTRIC SIGN DEVICE Filed Sept. 25, 1964 2 Sheets-Sheet 2 ,0:i9 5 Q /Qcz 56 /5 7/0 INVENTOR.

C2 EEA/CE Q 61.456014/ TTENEYS United States Patent O "ice 3,210,872ROTATING ELECTRIC SIGN DEVICE Clarence 0. Glasgow, 2620 S. Yorktown,Tulsa, Okla. Filed Sept. 25, 1964, Ser. No. 399,234 6 Claims. (Cl.40-33) The present invention relates t-o rotating electrical signs andthe like, and more particularly, but not by way of limitation, relatesto a novel drive mechanism for rotating an electrical sign.

This is la continuati=on-inpart of my copending application Serial No.194,431, tiled May 14, 1962-, now Patent No. 3,153,292 for RotatingElectric Sign Device.

As is Well known to the average motorist, rotating electrical signs areextensively used by automobile service stations. These rotating signsgenerally comprise a la-rge sign member having the outline of the shieldor symbol of the particular oil company mounted atop a relatively tallpost or pedestal. The sign members are rotated about a vertical axis byan electric motor which is connected through a reduction gear box todrive a shaft connected to the sign member. Some type of commutatorrings are provided somewhere on the drive train for supplying electricpower t-o illuminate the rotating sign member. In most cases, thecombination electric motor and reduction gear box is so large as torequire a relatively large support pedestal in order to house the drivemechanism. Of course, this presents difficulties in designing anattractive pedestal, which is a very important con-sideration inadvertising. But by far the greatest ditiiculty encountered in use ofthis type drive mechanism is created by w-ind Igusts striking therotating sign member. T-he rotating sign member must be relatively largein order to be effective as an .advertising device.

Since the sign will invariably be positioned out-of-doors, the sign willybe subjected to very high wind gusts, which in the southwestern regionsof the country frequently reach 40 t-o 60 miles Iper hour. These gustsare by nature highly turbulent s-o that they invariably exert unevenforces o-n the ends of the rotating sign member, which produces sharpand severe jolts and backlashes to the gear train of the dlr-ivemechanism. Since the gear train is :a positive mechanical drive, it isusually unable to absorb the severe shocks and strains and frequentlythe gears fail. `In my copending application, there is disclosed acompact hydraulic system for driving rotating electrical signs whichpermits the reduction in size of the pedestals supporting such signs andthereby improving the appearance of the signs. A flexible torquecoupling is installed between the hydraulic motor 'and the shaft of thesign to -compensate for shock loads resulting primari-ly from windgusts.

It has been discovered that steady, strong breezes encountering rotatingelectric signs, constructed in accordance with my copending application,may pre-load the flexible torque coupling to such .an extent that suddengusts may cause a considerable increase in the fluid pressure within`the hydraulic drive system. The pressure increase occurs because theflexible torque coupling is stressed until it functions essentially as a`direct mechanical coupling between the hydraulic motor and the signshaft. Considerable pressure increases may also occur as a result ofextremely high velocity wind ygusts without the aid of the steadybreeze. However, the torque coupling alone has been found adequate toprotect the system from almost all wind gusts.

Placing the pressure relief valve in the hydraulic drive system whichalso includes the flexible torque coupling provides `a novel and highlyadvantageous drive system which is suitable for use with rotating signsregardless of the Wind conditions encountered.

3,210,872 Patented Oct. 12, 1965 Furthermore, the use of the adjustablerelief valve in combination with the llexible torque coupling permitsthe use of a smaller pump .and drive motor thereby providing a morecompact unit for installation. A smaller drive motor and pump can beused because they will not be subjected to large pressures or stallingof the sign which -could cause the motor .to overheat. If the signshould stall for any reason, the relief valve which is adjusted to openbelow a pressure which would damage any component will open t-o preventstalling the drive motor.

Therefore, this invention provides a highly useful combination of-exible torque coupling and adjustable pressure relief valve in ahydraulic drive system for rotating electric signs that provides for theefficient operation of the sign while protecting each component in thesystem and, simultaneously permitting the safe use of components ofminimum size to attain a very compact installation.

Therefore, it is an important object of the present invention to providea drive mechanism for rotating an electrical sign which will .absorb allshocks, jolts and backlashes caused by wind forces and the like.

Another very important object of the present invention is to provide ahighly compact drive mechanism for a not-ating electrical sign which maybe located in a relatively small tubular support pedestal.

Still another object of this invention is to provide ahighly novelflexible torque coupling which may be economically manufactured andwhich may also be utilized as a commutat-or for supplying electricalpower to the rotated sign. Y

Yet .another object of the present invention is -to provide a drivemechanism of the type described through which the electrical connection.to the rotating sign can be very easily made.

An additional object of the present invention Iis to provide a drivemechanism of the type described which can be operated during theoccurrence of high velocity wind gusts without damaging the hydraulicdrive system.

A further object of the present invention is to provide a drivemechanism of the type described which may be easily installed to driveexisting rotating signs.

A still further object of the present invention is to provide a drivemechanism of the type described which may be located either within thebase or within the top of a support pedestal.

Another object of the present invention is to provide a drive mechanismof the type described which may be very easily serviced and which has anexceedingly long working life.

Still another object of the present invention is to provide a drivemechanism of the type described which has a highly simplifiedconstruction, a minimum of working parts and which can be economicallymanufactured, installed and operated.

Many additional objects and advantages will be evident to those skilledin the art from the following detailed description and drawings,wherein:

FIG. 1 is a side elevational view partly in section of a drive mechanismconstructed in accordance with the present invention;

FIG. 2 is a cross sectional view taken substantially on lines 2 2 ofFIG. 1;

FIG. 3 is a schematic diagram of a rotating sign device constructed inaccordance with the present invention;

FIG. 4 is an elevational view in section of the drive mechanism of FIG.1 slightly modified for placement at the top of a pedestal;

FIG. 5 is a cross sectional view taken substantially on line 5-5, and,

FIG. 6 is a schematic view of lanother sign device constructed inaccordance with the present invention.

Referring now to the drawings, and more particularly to FIG. 1, acompact drive mechanism constructed in accordance with the presentinvention is indicated generally by the reference numeral 10. The drivemechanism comprises a cylindrical housing 12 which may .be fabricatedfrom a short length of six or eight inch pipe. A flange 14 is welded orotherwise connected to the bottom of the housing 12. A plurality ofbolts 16 pass through apertures in the flange 14 for connecting thedevice to a base plate 18, for example, when the drive apparatus is usedin the sign construction illlustrated in FIG. 3. However, those skilledin the art will realize that the housing 12 may be bolted to anysuitable support frame as hereafter described in greater detail.

A rotary hydraulic motor 20 is connected by countersunk bolts 22 to atorque plate 24 which is secured within the housing 12 by countersunkbolts 26. The rotary hydraulic motor 20 has an output shaft 28 which isvertically disposed along the axis of the cylindrical lhousing 12. Therotary hydraulic motor 20 is of con- -ventional sign design and iscommercially available. The hydraulic motor 20 has a maximum diameter ofonly a few inches so that it may be easily disposed within thecylindrical housing 12. The rotary hydraulic motor- 20 is preferably ofthe type employing only a rotary ring Igear which revolves about apinion which is attached to the output shaft 28. As the gear is rotatedby hydraulic power fiuid, the pini-on is rotated at a reduced speed ofapproximately one-sixth the rate of rotation of the ring gear. Thehydraulic power fluid is supplied to the hydraulic motor through a pairof tubular conduits and 32 which may be fabricated from copper tubing orsimilar flexible conduit material. The conduits 30 'and 32 may passthrough a conveniently located aperture 34 in the cylindrical housing 12and extend to a hydraulic fluid pump hereafter described. A conduit 31connects the conduit 30 with the conduit 32.

A pressure-actuated, relief valve 35 is operably connected in theconduit 31. The valve 35 includes a valve body A36, arranged to beconnected in the conduit 31; a valve seat 37 in the valve body,surrounding a flow passageway; a spring-biased valve member 38 moveable`in the body 36 toward and away from the seat 37 to open and close thepassageway;4 and an adjustingl screw 39 for changing the force holdingthe valve member 38 on the seat 37, whereby the valve 35 can be adjustedto open at a selected pressure. The adjusting screw 39 is adjusted sothat the valve member 38 will move away from the seat 37 at a pressureabove the pressure required to rotate the sign 172, but below thepressure which would result in damage to the system or stall out themotor driving the hydraulic pump as hereinafter described.

The output shaft 28 of the rotary hydraulic motor y20 is keyed to aflexible torque coupling, indicated generally by the reference numeral40. Various details of construction of the flexible torque coupling 40are shown in FIGS. l, 2, 4 and 5, as will presently be described. lThetorque coupling 40 comprises a mass of butyl rubber 42 whichissandwiched between and bonded to upper and lower coupling plates 44and 46 respectively. A

`plurality of perforated plates 48, and 52 are disposed in parallelrelationship at right angles to the axis of rotation of the coupling andare molded in the interior of the rubber mass 42. The upper and lowercoupling plates 44 and 46 are bonded to the rubber mass 42 by anysuitable means, but preferably are bonded to the mass during the moldingof the coupling 40, in which case the coupling plates 44 and 46 serve asthe end of the casting mold. The surfaces of the coupling plates 44 and46 are preferably provided with annular grooves 54 and 56 and radiallyextending bores 58 and 60, as best seen in FIGS. 1 and 5. Similarly, theseveral plates 48, 50 and 52 are provided with a plurality of apertures62, as typically illustrated in the plate 52 in FIG. 2.

An axial bore 64 is provided along the axis of the torque coupling 40and extends through the upper coupling plate 44, the mass of butylrubber 42 and the three perforated plates 48, 50 and 52. Another axialbore (not referenced) extends partially through the lower coupling plate46 for receiving the drive shaft 28 of the rotary hydraulic motor 20. Apair of keys 66 provide a positive couple between the drive shaft 28 andthe lower coupling plate 46.

It will be noted that the outer circumferential edges of the threeplates 48, 50 and 52 extend slightly beyond the periphery of the body ofbutyl rubber 42 so as to provide electrical slip rings or commutatorrings for purposes to be hereafter described in greater detail. It willalso be noted that the plates 48, 50 and 52 extend inwardly to the bore64 so as to provide electrical conductors from the exterior surfacethrough the mass of butyl rubber 42 to the axial bore 64. In thisconnection, it will also be noted that the plates 48, 50 and 52 areelectrically insulated one from the other and from all other conductivematerial by the body of butyl rubber 42.

It will be obvious to those skilled in the art that the flexible torquecoupling 40 may be very easily fabricated. For example, the upper andlower coupling plates 44 and 46 and the perforated plates 48, 50 and 52may be cast or machined in any suitable manner. Then the coupling plates44 and 46 may be used to form the ends of a mold while the perforatedplates 48, 50 and 52 are held in spaced parallel relationship within themold. Butyl rubber 42 may then be injected into the mold through theaxial bore 64 and will easily pass between the five plates and willpenetrate the annular grooves 54 and 56 and the radial bores 58 and 60of the coupling plates 44 and 46, respectively, to insure an integralbond having as much strength as the butyl rubber itself. The radialbores 58 and 60, in addition to assuring a maximum strength bond, permitgases to escape and also provide an indication of when the mold iscompletely filled with rubber to assure a top quality product.Similarly, the butyl rubber will be injected into the large plurality ofapertures 62 in the commutator plates 48, 50 and 52 to provide anintegral mass of butyl rubber and assure positive bonding to the threecommutator plates which also serve to stiifen and strengthen the torquecoupling 40 as hereafter described.

Electrical brushes 70, 72 and 74 are held in sliding contact with theouter peripheries of the plates 48, 50 and 52, respectively, bybrush-holder arms 76, 78, and 80, respectively. The brushes are receivedin counterbores (not referenced) in the respective arms. Conductors 82,84 and 86 are electrically connected to the brushes and pass throughbores in the brush-holder arms. The three conductors may then beconveniently bound together by electrical tape and as a collective lead87 passed through an aperture 88 in torque plate 24 and extended alongthe path `of the hydraulic fluid conduits 30 and 32 to a source ofelectrical power.

The brush-holder arms 76, 78 and 80 are pivotally supported on avertically disposed stud 90 which may be conveniently threaded into thetorque plate 24. The brush-holder arms 76, 78 and 80 may conveniently befabricated from wood and may be held in spaced relationship by suitablebushings 92, 94 and 96 which are disposed around the stud 90. A nut 97may be threaded onto the upper end of the stud 90 to complete theassembly. A second stud 98 is also threaded into the torque plate 24and, as best seen in FIGS. 2 and 5, is provided with a longitudinallyextending groove 100. A coil spring such as indicated by referencenumeral 102 is connected to each .of the brush-holder arms and isreceived in the longitudinal groove 100 to continually exert a biasurging the respective brush-holder arms toward the flexible torquecoupling 40 so as to firmly press the several brushes against the outercircumference of the plates 48, 50 and S2 to insure continuouselectrical contact as the torque coupling the valve member 38 moves awayfrom the seat 37, per- 40 rotates. mitting flow through the valve 35from the conduit 30 An adapter 104 which is comprised of a plate portiondirectly into the conduit 35 from the conduit 30 directly 106 and ashank portion 108 is connected to the upper into the conduit 32 withoutentering the motor 20. When coupling plate 44 by countersunk bolts 110.The adapter 5 the fluid pressure drops below the opening pressure of the104 is provided with an axial bore 112 which registers valve 35, thevalve 35 closes and normal circulation is with the bore 64 andpreferably is of the same diameter. resumed. Thus, it can be seen thatthe inclusion of the A tubular drive shaft 114 is telescoped over theshank valve 35 and the conduit 31 permits the use of the rotatportion108 and is connected thereto by a shear pin 116 ing sign in relativelyadverse wind conditions without which may be retained in place bywedging or any other the danger of overloading or damaging any portionof suitable method. The drive shaft 114 extends upwardly the hydraulicdrive system or of the motor 164 driving through a hollow pedestal andis connected to rotate a the hydraulic pump 162.

sign member as hereafter described in greater detail in When the sign isto be installed in an area wherein conconnection with FIG. 3. siderablewind gusts are to be anticipated, lthe adjust- A thrust bearingindicated generally by the reference ing screw is preferably set topermit the valve 35 to open numeral 120 is provided to support the loadimposed on at a pressure considerably below the maximum safe op thedrive mechanism. The thrust bearing is comprised of erating pressure ofthe hydraulic system. The valve 35 an outer race 122, an inner race 124and a plurality of is set to open at such a low pressure to prevent overprestapered roller bearings 126 which are spaced by a consuring thesystem due to the occurrence of high pressure ventional spacer ring (notillustrated). The thrust bearpulses if the sign is suddenly stopped oreven reversed ing 120 is received within a counterbore in the upper by astrong wind gusts.

end of the cylindrical housing 12 and the outer bearing On the otherhand, if the sign is to be installed in an race 122 rests on an annularshoulder 127 formed by a area wherein the wind blows constantly, butwithout counterbore 128. The outer bearing race 122 is prefergustng, theadjusting screw 39 can be set to permit ably press-fitted within thecounterbore so as to prevent the valve 35 to open a higher pressurewithout endangerrotation and subsequent loosening of the bearing race.ing the components in the hydraulic system. The inner bearing race 124may be press-fitted around The reservoir 166, the hydraulic pump 162 andthe the upper coupling plate 44 and abut against the plate electricmotor 164 may conveniently be located within portion 106 of the adapter104, so that the thrust bearing the service station in the general areaof the air compres- 120 will support any vertical load imposed on thebearing 30 sor, for example. The drive mechanism 10 is positioned by thedrive shaft 114. within a tapered pedestal 170 and is supported on the Acylindrical plug insert 130 fabricated from wood, base plate 18, whichis connected to a suitable foundaplastic or any other similarnonconductive material is tion. A sign member 172 is rotatably supportedatop disposed in the bores 64 and 112. Three bowed leaf the pedestal 170by a suitable bearing 174. The tubular springs 132, 134 and 136, as bestseen in FIG. l, are 35 drive shaft 114 extends vertically upwardly fromthe connected to the plug insert 130. The springs 132, 134 drivemechanism 10 and is connected to the rotating sign and 136 arefabricated from a conductive material and 172. The electrical conduits148 extend through the are axially spaced along the plug insert tocontact the tubular drive shaft 114 to the interior of the signmeminne-rmost edge of the ring plates 52, and 48, respec ber 172. Usedhydraulic iluid from the drive mechanism tively. The springs 132, 134and 136 are also cireum- 40 10 is returned through the flexible conduit32 to the ferentially spaced around the plug insert 130 so that threereservoir 166. y

grooves 140, 142 and 144 may be provided in the plug Another rotatingsign device is indicated generally by insert 130 to receive threeconductors indicated collecthe reference numeral 180 and is illustratedschematicaltively by the reference numeral 146 in FIG. l. The ly in FIG.6, and in greater detail in FIG. 4. The same lower ends of theconductors 146 are electrically con- 45 source of hydraulic power fluid161 is utilized in com nected to the three springs 132, 134 and 136. Theconbination with the sign device 180 including the hydrauli` ductors areinsulated by a conventional insulating sheath pump 162, which is drivenby the elect-ric motor 164 148, and extend upwardly through the driveshaft 114 to and the hydraulic fluid reservoir 166. Hydraulic ui theelectrical sign driven by the shaft as hereafter deis also suppliedthrough the flexible conduit 30 and scribed. It will be noted that pluginsert 130 rests on the 50 returned through the exible conduit 32 to thereservo upper surface of the bottom coupling plate 46 and, as 166. Itshould also be pointed out that the relief vali best seen in FIG. 4, issufficiently short as to permit the 35 is utilized with the hydrauliccircuit illustrated shear pin 116 to be inserted through the drive shaft114 FIG. 6. The relief valve 35 and conduit 31 are inte and the shankportion 108 of the adapter 104. However, posed in the circuit of FIG. 6in the same manner the plug insert 130 preferably has a tab portion 150which 55 described in connection with FIG. 3 and serve the sai extendsbeside the shear pin 116 to a point above the purpose as describedtherein. upper end of the shank portion 108 so that the plug in- Thesign device 180 has a tubular pedestal 182 wh? sert 130 may convenientlybe removed from the bores 112 may conveniently be formed from a joint ofsix or ei; and 64. inch pipe supported by a concrete base 184. The dr Atypical signv installation in accordance with the mechanism 10 isslightly modified as hereafter descril present invention is' indicatedgenerally by the reference and accordingly is designated by thereference -numt numeral 160 and is shown in the schematic diagram of10a. The modified drive mechanism 10a is positio FIG. 3. A source ofhydraulic power fluid indicated atop the pedestal 182 and rotatablysupports a sign l generally by the reference numeral 161 is comprised ofThe uid conduits and electrical power leads extend a hydraulic pump 162,driven by a suitable electric motor wardly through the pedestral 182 tothe drive mechar 164, which withdraws hydraulic fluid from a reservoir10a. 166 through a strainer 168. The hydraulic pump forces Referring nowto FIG. 4, the modified drive me the hydraulic fluid through the conduit30 to the hydraulic nisrn 10a is essentially the same as the drive mechamotor 20 of the drive mechanism 10 and from the motor 10 illustrated inFIG. 1. Accordingly, all parts of the 20 through the conduit 32 to thereservoir 166. y 70 mechanism 10a which are identical in construction tDuring normal operation, fluid will continue to cirparts of the drivemechanism 10 are indicated by the culate as described, but when the signencounters a large reference numeral The primary difference betweeamount of wind resistance, the result will be an increase drivemechanism 10a and the drive mechanism 10 i in the pressure of the uid inthe system. If the presthe housing 12a, which includes an exterior flangsure reaches the opening pressure of the relief valve 35, on its lowerend, isprovided with an extension 188i and comprises an outer race 194which is supported by the shoulder 190, an inner race 196, and aplurality of tapered roller bearings 198.

A short drive shaft 200 is connected to the sign member 186 and istelescoped the adapter 104. Th

ber at approximately six r.p.m. while delivering maximum torque.

limiting one, be fabricated 'forated plates gs for providing electricalpower to the rotating sign nbers 172 and 186. This results in a'entional power leads for alternating current, toer with a ground wire,may be utilized for maximum y.

:cause of its very compact size, the drive mechanism in a very simpleand Further, locating the drive can be made therein without departingfrom the spirit and scope of the invention as defined by the appended 5claims.

flexible torque coupling means interconnecting the drive shaft and theoutput shaft, the exible torque coupling means being fabricated tricallynonconductve material,

a plurality of electrically conductive slip rings on the flexible torquecoupling, the slip rings being electrically insulated one from the otherby the resilient electrically nonconductive material;

brush means for making sliding electrical contact with each of the sliprings;

electrical circuit means connected to the brush means for supplyingelectrical power to the brush means; and

electrical circuit means interconnecting the slip rings and theelectrical sign.

2. A rotating sign device comprising:

a sign support pedestal;

a sign rotatably supported by the pedestal;

a drive shaft vertically disposed within the pedestal and connected torotate the sign;

a rotary hydraulic motor connected to shaft and thereby rotate the sign;

a source of hydraulic power uid connected to the hydraulic motor forsupplying hydraulic Huid under pressure for driving the motor; and

rotate the drive 3. The sign device of claim 2 wherein said hydraulicpower fluid source includes:

a hydraulic pump connected with said motor; means for driving said pump;a fluid reservoir connected with said pump and with said motor; and,said relief valve means being operably disposed between said pump andmotor and including a valve body having a flow passageway therethroughconnected with said power fluid source and having a seat surroundingsaid passageway, a valve member disposed in said valve body and movabletoward and away from said seat, a spring member in said valve bodybiasing said valve member toward said seat, and an adjusting screw insaid valve body for imposing a load on said spring whereby said valvemember will move away from said seat at a preselected pressure. 4. Adrive mechanism for rotating an electrical sign rotatably supported by apedestal, the drive comprising:

a vertically disposed tubular housing;

a thrust plate connected within the tubular housing at a midpointthereof, the thrust plate having a central aperture;

a rotary hydraulic motor connected to the thrust plate, the hydraulicmotor having a rotary output shaft extending through the aperture to apoint above the thrust plate;

a source of hydraulic power fluid connnected to the motor for operatingthe motor;

relief valve means operably connected between said motor and lluidsource and openable at a preselected uid pressure exceeded by pressuresimparted to said power fluid by wind gusts acting on said sign, saidrelief valve means thereby preventing the fluid pressure from exceedingthe preselected value and damaging said motor or power uid source;

a exible torque coupling comprising a mass of resilient, nonconductivematerial having opposite ends, and rst and second coupling plates bondedto the opposite ends, the first coupling plate being connected to theoutput shaft of the motor for rotation of the mass about an axis ofrotation generally perpendicular to the coupling plates, a plurality ofelectrically conductive circular discs embedded in the mass, the discsbeing spaced apart and disposed at substantially right angles to theaxis of rotation with the peripheries of the discs exposed, and a boreextending axially through the mass and through the discs;

electrical brush means supported by the thrust plate in sliding contactwith the periphery of each of the discs; and,

electrical circuit means extending through the bore and electricallyconnected to each of the discs.

5. A rotating sign device comprising:

a vertically disposed tubular pedestal;

a thrust plate connected within the tubular housing at a point adjacentthe upper end thereof;

a rotary hydraulic motor Connected t the thrust Plate,

l0 the motor having an output shaft extending above the thrust plate;

a source of hydraulic power fluid connected to the motor for operatingthe motor;

relief valve means operably connected between said motor and fluidsource arranged to open at a preselected lluid pressure lower thanpressures developed upon said power uid by wind gusts acting on saidsign in a direction opposite the direction of rotation, said reliefvalve means thereby preventing the iluid pressure from exceeding thepreselected value and damaging said m-otor or power uid source;

a flexible torque coupling comprising a mass of resilient, nonconductivematerial having opposite ends and first and second coupling platesbonded to the opposite ends, the first coupling plate being connected tothe output shaft of the motor for rotation of the mass about an axis ofrotation generally perpendicular to the coupling plates, a plurality ofelectrically conductive circular discs embedded in the mass, the discsbeing spaced apart and disposed at substantially right angles to theaxis of rotation with the peripheries of the discs exposed, and a boreextending axially through the second coupling plate, through the massand through at least all but one of the discs;

electrical brush means supported by the thrust plate in sliding contactwith the periphery of each of the conductive discs;

a tubular drive shaft connected to the second coupling plate andextending vertically upwardly through the pedestal;

a sign member connected to the tubular drive shaft and rotatablysupported atop the pedestal;

electrical circuit means connected to the brush means for supplyingelectrical power thereto; and,

electrical circuit means connected to each of the discs and extendingthrough the bore in the flexible torque coupling and through the tubulardrive shaft to the sign member.

6. The rotating sign device of claim 5 wherein said relief valve meansincludes:

a valve body having a flow passageway therethrough connected with saidpower lluid source and having a seat surrounding said passageway;

a valve member disposed in said valve body and movable toward and awayfrom said seat;

a spring member in said valve body biasing said valve member toward saidseat; and,

an adjusting screw in said valve body for imposing a load on said springwhereby said valve member will move away from said seat at a preselectedpressure.

References Cited by the Examiner UNITED STATES PATENTS 2,622,611 12/52Stark 137-116 3,153,292 10/64 Glasgow 40-39 EUGENE R. CAPOZIO, PrimaryExaminer.

LAWRENCE CHARLES, Examiner.

1. A ROTATING SIGN DEVICE ADAPTED FOR USE IN A CLIMATIC ENVIRONMENTINCLUDING WINDY CONDITIONS COMPRISING, IN COMBINATION: A SIGN SUPPORTPEDESTAL; AN ELECTRICAL SIGN ROTATABLY SUPPORTED BY THE PEDESTAL; AROTARY HYDRAULIC MOTOR HAVING A ROTATING OUTPUT SHAFT AND SUPPORTED BYTHE SUPPORT MEANS; A HYDRAULIC POWER FLUID SOURCE CONNECTED TO THE MOTORFOR SUPPLYING HYDRAULIC FLUID UNDER PRESSURE TO OPERATE THE MOTOR;RELIEF VALVE MEANS OPERABLY CONNECTED BETWEEN SAID MOTOR AND SAID FLUIDSOURCE AND OPENABLE AT A PRESELECTED FLUID PRESSUR, THEREBY PREVENTINGTHE FLUID PRESSURE DEVELOPED BY WIND GUSTS ACTING ON SAID SIGN FROMEXCEEDING THE PRESELECTED FLUID PRESSURE VALUE AND DAMAGING SAID MOTOROR POWER FLUID SOURCE; A DRIVE SHAFT CONNECTED TO ROTATE THE SIGN;FLEXIBLE TORQUE COUPLING MEANS INTERCONNECTING THE DRIVE SHAFT AND THEOUTPUT SHAFT, THE FLEXIBLE TORQUE COUPLING MEANS BEING FABRICATED FROM ARESILIENT ELECTRICALLY NONCONDUCTIVE MATERIAL, A PLURALITY OFELECTRICALLY CONDUCTIVE SLIP RINGS ON THE FLEXIBLE TORQUE COUPLING, THESLIP RINGS BEING ELECTRICALLY INSULATED ONE FROM THE OTHER BY THERESILIENT ELECTRICALLY NONCONDUCTIVE MATERIAL; BRUSH MEANS FOR MAKINGSLIDING ELECTRICAL CONTACT WITH EACH OF THE SLIP RINGS; ELECTRICALCIRCUIT MEANS CONNECTED TO THE BRUSH MANS FOR SUPPLYING ELECTRICAL POWERTO THE BRUSH MEANS; AND ELECTRICAL CIRCUIT MEANS INTERCONNECTING THESLIP RINGS AND THE ELECTRICAL SIGN.